Apparatus for conditioning air



Nov. 2, 1937. J. A. GUYER f 2,097,520

APPARATUS FOR CONDITIONING AIR Filed Jan. 1s, 195e f `Patented Nov. 2 1937 APPARATUS FOR CONDITIONING AIR Jesse A. Guyer, Mount Vernon, Ill., assignor to J. P. Devine Manufacturing Co., Inc., Mount Vernon, Ill., a corporation of Illinois Application January 16, 1936, serial No. 59,336

7 Claims.

'I'his invention relates to apparatus for conditioning air, and with regard to certain more specic features, to such apparatus using a solid refrigerant, such as carbon dioxide (dry ice),

as a refrigerating medium.

Among the several objects of the invention may be` noted the provision of apparatus for conditioning air in which a solid refrigerant, such as carbon dioxide is used as a refrigerating medium, 1 l0 and in which the full heat absorbing capacity of the solid carbon dioxide is utilized in an economical manner; the provision of apparatus of the class described which is particularly adapted for the conditioning of air in moving vehicles, buildings, and the like; the provision of apparatus of the class described which requires no secondary refrigerating medium; the provision of apparatus for conditioning air which is so constituted as to achieve a substantially constant and controllable cooling effect over a substantial length of time; and the provision of apparatusof the class described which is economical to carry out and construct. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts, which will be exemplified-in the structures hereinafter Adescribed, and the scope of the application of which will be indicated in the following claims. ,Inthe accompanying drawing, in which are illustrated several of 'various possible embodiments of the invention,

Fig. 1 is a diagrammatic layout of an air conditioning system utilizing the present invention; Fig. 2 is a diagrammatic cross section of a refrigerating chamber;

Fig. 3 is a diagrammatic longitudinal section of the chamber shown in Fig. 2, and taken substantially along line 3 3 of Fig. 2; v

Fig. 4 is a diagrammatic cross section similar to Fig. 2 illustrating an alternative form ,of refrigerating chamber;

Fig. 5 is a diagrammatic longitudinal section of along line 5-5 of Fig. 4

Fig. 6 is a fragmentary layout alternative to the layout of Fig. 1; and,

Fig. 7 is another alternative fragmentary layout.

. spendingparts throughout the several -views of the drawing. Y

A principal objection to many of the refrigerating units of air conditioning systems in use today the chamber of Fig. 4, and taken substantially' Similar lreference characters indicate correisthat they require a circulating secondary refrigerant, that is to say, a circulating liquid which, in a chilled condition, absorbs heat from the air being conditioned, and delivers'up said heat to a heat-absorbing or refrigerating unit where it is cooled and then rccirculated. Such a system for example has been used with a heatabsorbing or refrigerating unit employing solid carbon dioxide as the heat-absorbing or refrigerating material. However, such a conditioning system is disadvantageous under many circumstances, such as for example, in moving vehicles such as railroad cars, buses, trucks and passenger automobiles, because in the event of a wreck, the secondary refrigerant liquid is frequently released from the system into the surroundings, rendering the equipment inoperativeuntil it is replaced. 'Ihis liquid frequently is either poisonous or at least, unpleasant. Even without wrecks, the leaks that normaly occur in the liquid circuit in the course of time permit the escape of this secondary refrigerant, and therefore its use is objectionable.

- The present invention provides an air conditioning system wherein dry ice is used as the heat-absorbing medium but wherein no secondary refrigerant isv employed.

Fig. 1 is a diagrammatic view showing the several parts of an air conditioning system employing-the present invention. Numeral I indicates an air blower or fan which has an air inlet 2 and a discharge outlet 3. The blower or fan I may be of any type customarily used for this purpose. The outlet 3 delivers the air under suitable velocity and pressure to a tunnel indicated generally by numeral 4 and which comprises a plurality of sections. The air rst passes through section 5, which is a heating unit. This unit may be of any of the various types customarily used. For example, it may be a steam heating unit, in which event steam is admitted through an inlet '6 and discharged through an outlet l. The heating unit 5 is ordinarily used only when the ambient airl is too cold, and hence it is not ordinarily employed when the ambient air is too hot and the present invention is used for chilling the air.

'Ihe nextsection in the tunnel 4 is indicated by numeral 8 and comprises a mixing unit. 'I'his merely comprises a length of conduit with baiiies 9 therein so that the air is forced to travel through a tortuous path and hence becomes uniformly mixed, for example, if the heating unit 5 is being used.

From the mixing unit 8 of the tunnel 4, the air passes to a cooling unit l0, with which the presto be conditioned.

the chamber sure, say two pounds;

- because of the pressure The cooling unit I0 has an inlet I2 and an out-` let I3. 'I'he inlet I2 is fed, by a conduit I4, with chilled carbon dioxide gas which is produced in a chamber I5. The construction of this chamber I5 is one of the particular features of this present invention and will be described-in detail hereinafter. For present purposes, it is sufcient to state that the chamber I5 contains solid carbon dioxide or dry ice, and is provided with means for 4permitting the circulation of carbon dioxide gas therethrough.

The outlet I3 of the cooling unit I0 delivers into a conduit I6 which in turn delivers into a blower` or pump 31 which discharges through a conduit 38 to the chamber I5.

There is thus provided a continuous recirculation of carbon dioxide gas from the chamber I5 through the conduit I4 to the cooling unit I0, thence through the conduit I6 to the circulating blower 31 and through the conduit 38 back to I5. The circulated carbon dioxide gas is generated by the constant evaporation of the solid carbon dioxide in the chamber I5. Inasmuch as the solid carbon dioxide is constantly evaporating, this would mean, were no appropriate preventative stepsdtaken, that the amount of carbon dioxide gas in the system Iwould constantly be increasing.v In order to maintain a constant volume of carbon dioxide gas in the circulating system at'the desired pressure, a discharge line I1 branching from the conduit I8 is provided. The discharge line I1 has a pressure relief or regulatorvalve I8 therein. The regulator valve I8 is set to a predetermined presn and it automatically operates to discharge carbon dioxide gas whenever the pressure in the circuit rises above said two pounds. The value given, two pounds, is of course by way of example only, as any suitable pressure can be used at venience.

Just ahead ofthe connects to the inlet I2, there is provided a thermostatic regulator valve I9, whichis controlled by a thermostat 20 positioned in the region for which the air is being conditioned. The regulator valve 4 I9, when the temperature of the region rises too high, opens to allow a slow flow of cold carbon dioxide gas to the cooling unit I0 and hence to reduce the temperature of the air flowing to said region. Conversely, when said region becomes too cool, the thermostatic. valve I9 operates the regulating valve I9 to diminish or cut oif the ow of carbon dioxide gas to the cooling unit Ill, and hence the air owing through the unit is then not vso greatlychilled.

All conduits are vpreferably heat-insulated.

When the regulator valve I9 is closed there is a tendency for the carbon dioxide gas in the conduit I4 to build up an undesirably high pressure producedby the blower 31, provided the blower is of a positive displacement type. In order to prevent such accumulating pressure, a by-pass line 2I is provided from the conduit I4 to the conduit I6; It is connected into the conduit I4 ahead of the regulator valve I9. In the conduit 2| there is provided a pressure regulating or release valve 22. This valve 22 opens upon the exceeding of a predetermined the operators ,con-

point where the conduit I4 .are numerous. The total heat-absorbing capacity of the solid carbon dioxide in the chamber Il is utilized, without substantial the heat from the air in the tunnel 4. This is vtrue because the heat absorbing medium in the cooling unit Ill is carbon dioxide gas which is promptly recirculated to the chamber I5, where it delivers up the heat it has absorbed to the solid carbon dioxide and in so doing, not only vaporizes more solid carbon dioxide, but also becomes chilled itself. The carbon dioxide gas in the line I4 is Athus thoroughly chilled. It comprises both recirculated gas from the lines I8 and 38, and fresh gas generated by evaporation of solid carbon dioxide in the chamber I5. In

waste, to absorb order to keep aregulated volume, and hence a regulated pressure of carbon dioxide gas in the system, the relief valve I8 functions to discharge a necessary amount of carbon dioxide from the circuit. However, the discharged carbon dioxide is not in its chilled condition, but in the warmed 'condition as a result of the absorption of heat from the air being conditioned.

If the thermostat 20 so functions as to close the regulating Valve I9, then cold carbon dioxide gas passes from the conduit I4 throughA the bypass conduit 2l to the conduits I8 and 38, and thence back to the cooling chamber I5. Inasmuch as no heat has been absorbed in this flow, no heat is delivered up to the solid carbon, dioxide in the chamber I5, and hence further evaporation of the solid carbon dioxide in the chamber does not take place to any substantial extent. Hence, it will be seen closed (indicating that no cooling is required in the una lo), substanuauy no sono carbon ca oxide is being consumed, and the solid carbon dioxide is being saved until conditions require that its heat-absorbing capacities be utilized.

The automatic manner in which the cooling circuit functions is one of4 the principal advantages of the invention. The only attention required is that a suitable quantity of solid carbon dioxide be maintained in the chamber I5 at all times. l 'Ihe controlling features of the invention may likewise be obtained by the systems shown in Figures 6 and '1, among others. The system of Fig. 6, for example, differs from the Fig. 1 system i in that the by-pass line 2| Aand regulator valve 22 are omitted, the blower 31 being of a fan type. A characteristic of such a' blower is that it will not build up a pressure in excess of a predetermined value. Hence, when the thermostatic valve I9 closes, the pressure in line I4 builds up only slightly, and thereafter all circulation ceases, conserving the heat-absorbing capacity of the refrigerant.

In Fig. 1 a different system is shown wherein the thermostat 20, instead of controlling a valve, directly controls the operation of the blower 81. which may now be of either apositive displacement or a pump type. For example, when the ambient temperature drops too low, the thermostat 20 shuts oi the blower 31, and circulation ceases, thus effecting the desired conservation.

As has been indicated hereinbefore, the construction of the chamber I5 is one of the principe; features of the present invention. Figures i and 3 illustrate one form of the chamber, an(

that when .the valve Il is Figures 4 and 5 illustrate another form of the chamber. Referring now more particularly to Figs. 2 and 3, it will be seen that the chamber I comprises a rectangular box 23 formed of a good heat-insulating material, such as concentric metal boxes with a cork iller. The top 24 ofthe box 23 is illustrated as being removable for the purpose of filling the box 23, but it will be understood. that any other section of the box 23 may be made removable for this "purpose if desired. The box 23 is provided with a false bottom 25 which is perforated at frequent intervals as indicated at numeral 26. 'I'he false bottom provides a passage 21 of rectangular shape at the bottom of the box. An inlet opening 28 is provided at one end of the box 'for connection of the passage 21 to the conduit 38, While an outlet opening 29 at the other end of the box connects the passage 21 to the conduit-l4. Extending downwardly from the false `bottom 25 but terminating short of the bottom of the box 23, are a number of iins. 'I'he ins 30 as well as the false bottoml 25 of the box 23, are usually made of metal so that they have a high heat conductivity. l

A partition 3| is provided at the outlet end of the box 23, extending entirely across said box from the false bottom 25 upwardly almost to the top of the box. The partition 3l provides a passage 32 which communicates with the passage 21'at the outlet port 29.

In operation, commercial rectangular blocks of solid carbon dioxide, indicated by numeral 33, are placed in the box 23, resting upon the false bottom 25. Relatively heated carbon dioxide gas enters the box through the inlet opening 28 and passes along the passage-21. The carbon dioxidek gas delivers up its heat to fins 30 and the false bottom 25, which'are kept cold by their contact with the solid carbon dioxide. The absorbing of the heat so delivered causes the solid carbon `dioxide to vaporize, and the gaseous carbon-dioxide thereby generated passes out through the perforations26 to join the ow of carbon dioxide gas in the passage 21. Other carbon dioxide gas generatedfrom the solid carbon dioxide blocks passes downwardly from the top of the box through the passage 32 tojoinv the flow of carbon dioxide gas at the outlet 29. The carbon dioxide gas flowing out at the outlet 29 accordingly comprises fresh, cold carbon dioxide gas generated (from the carbon dioxide, and cooled carbon dioxide gas which entered at the inlet 28.

Because the relatively heated carbon dioxide gas entering at the inlet 28 delivers up its heat to substantially only one surface of a solid carbon dioxide block 33, namely the surface in contact with thefalse bottom 25, substantially all evaporation of said solid carbon dioxide block 33 occurs at said surface. Hence, as operations continue,

mitted t'o the chamber I5 in such manner that it contacted the solid carbon dioxide blocks 33 indiscriminately, or over substantially the entire surface thereof, the blocks 33 would evaporate substantially uniformly over their entire surfaces, and as they evaporated, their surface area would area would mean that the cooling effect on the incoming relatively heated carbon dioxide gas would constantly diminish, until such a time as substantiallyI all of the solid carbon dioxide was used up, when the cooling effect would be negligible. However, by use of the chamber of the present invention, the evaporation of the solid carbon dioxide, as has been explained, is maintained almost entirely-at one surface, and pro-J vision has been made for keeping said surface at substantially a constant area, so that a uniform cooling effect is obtained even as the quantity of solidcarbon dioxide in the box 23 becomes less and less. l'

Figures' 4 and 5 show amodied form of box 23 wherein the area of the surface provided for cool-` constantly decrease. 'I'his decreasing surface ing the relatively heated carbon dioxide gas is increased, and hence the cooling capacity of the box is increased Without sacrificing any of the advantages above indicated. Instead of'the flat false bottom of the embodiment of Figures 2 and 3, this embodiment has a trough-shaped false bottom 34, which is perforated and carries flnsas in the prior embodiment. The surface area of the trough-shaped bottom 34, it will be understood, is considerably greater than the surface area of the flat false bottom of the prior embodi- I first time, no further delay is encountered if fresh rectangular 4blocks are placed in the box 23 sutilciently often that sufficient solid carbon dioxide is always present to lll the trough 34.

The principle underlying both embodiments of the chamber l5 as herein described-will vreadily be seen to comprise the provision of means whereby the solid carbon dioxide is evaporated over apredetermined constant surface area only.

It will be apparent that the present invention is useful not only with carbon dioxide, but also with any other substance which is readily obtained in solid form and which evaporates at proper temperatures to a vapor without going through an intermediate liquid phase.

The construction of the chamber I5, it is to be noted, may also be advantageously employed for the direct cooling of air', for (example, with blocks of water ice, because the water ice will melt andv cool the air current in substantially the sameuniform-area manner as heretofore described in connection with the solid carbon dioxide.'

In view of the above, it will be seenthat the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in carrying out tire above constructions without departing from the scope of the invention, it is intended that all matter contained in the above` description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense. v

I claim:

1. In an air conditioning system, a cooling unit,

and a\chamber, said chamber containing a substance in its .solid phase which passes, upon the absorption of heat, directly to its gaseous phase, conduit means connecting the outlet of said .chamber to the inlet of said cooling unit, conduit means `connecting the outlet of said unit tothe inlet of said chamber, whereby said substance in its gaseous phase, circulates from said chamber to said cooling unit and back to said chamber, anda bypass conduit around said cooling unit, said bypass conduit having a pressure regulating valve therein, whereby gas is by-passed through said by-pass conduit when the pressure of gas in said conduit leading from said chamber to said cooling unit increases above a predetermined amount.

v2. In an air conditioning system, a cooling unit, and a chamber, said chamber containing a substance in its solid phase which passes, upon the absorption of heat, directly to its gaseous phase, conduit means connecting the outlet of said chamber to the inlet of said cooling unit, conduit means connecting the outlet of said unit to the inlet of said chamber, whereby said substance in its gaseous phase circulates from said chamber to said cooling unit and back to said chamber,

means for regulating the amount of gas passing from the chamber to said cooling unit in accordance with the temperature of the region to be conditioned, and a by-pass conduit around said cooling unit, said by-pass conduit having a pressure regulating valve therein, whereby gas is by-Dassed through said by-pass conduit when the pressure of gas in said conduit leading from said chamber to said cooling unit increases above a predetermined amount. y

3. In an air conditioning system, a cooling unit,

and a chamber, said chamber containing a substance in its solid phase which passes, upon the absorption of heat, directly to its gaseous phase, conduitmeans connecting the outlet of said chamf the substance comprises carbon dioxide.

ber to the inlet of'said cooling unit, conduit means connecting the outlet of said unit to the inlet of said chamber, -whereby said substance in its gaseous phase circulates from said chamber to said cooling unit and back to said chamber,'means for regulating the amount of gas passing from the chamber to said cooling unit in accordance with the temperature of the region to be conditioned, a by-pass conduit around said cooling unit, said by- 'pass conduit having a pressure regulating valvetherein, whereby gas is by-passed through said by-pass conduit when the pressure of gas in said conduit leading from said chamber to said cooling unit increases above a -predetermined amount,

and pressure-regulated discharge means in the conduit connecting said cooling unit and said chamber. I V

4. The system as set forth in clain l in which 5. The system as set forth in claim 2 in which the substance comprises carbon dioxide.

6. The system as set forth in claim 3 in which the substance comprises carbon dioxide.

7. A chamber for the purposes described comprising a heat-insulating box, said box having a false bottom therein, meansfor admitting gas at 1` one end of said box under said false bottom, and vfor discharging gas at Athe other end of said box under said false bottom, the space above said false bottom being adapted to receive and store solid refrigerating material, and a passage at one end of said box extending upwardly from beneath said false bottom substantially to the top of said box, and being open at the top of said box, thereby to conduct gases from the space above said false bottom into the space below said false bottom. l

' JESSE A. GUYER. 

